I am the President of Coughlin Associates and a widely respected storage analyst and consultant. I have over 30 years in the data storage industry with multiple engineering and management positions at high profile companies.
I have many publications and six patents to my credit. I am also the author of Digital Storage in Consumer Electronics: The Essential Guide, which was published by Newnes Press. Coughlin Associates provides market and technology analysis (including reports on several digital storage technologies and applications and a newsletter) as well as Data Storage Technical Consulting services. I publish a Digital Storage in Consumer Electronics Report, a Media and Entertainment Storage Report, and a Capital Equipment and Technology Report for the Hard Disk Drive Industry.
I am active with SMPTE, SNIA, IDEMA, the IEEE Magnetics Society, IEEE CE Society, and other professional organizations. I am the founder and organizer of the Annual Storage Visions Conference (www.storagevisions.com), a partner to the International Consumer Electronics Show, as well as the Creative Storage Conference (www.creativestorage.org). I am also a Senior member of the IEEE, Leader in the Gerson Lehrman Group Councils of Advisors and a member of the Consultants Network of Silicon Valley (CNSV). For more information about me and my publications, go to www.tomcoughlin.com.

The Persistence Of Memory

Flash memory has been showing up in configurations that point to the arrival of persistent memory. Persistent memory retains its data in the host computer even when the power is turned off. Diablo Technology demonstrated flash-based DIMMs in the summer of 2013, a good candidate technology for initial persistent memory products. However flash memory cannot match the data rates that DRAM and especially SRAM (static random access memory) can provide and for this reason flash memory may augment but probably not replace DRAM (dynamic random access memory) and SRAM.

In order to create a viable persistent non-volatile memory we need NVM memory devices with data rates close to those of traditional DRAM and SRAM. MRAM (Magnetic Random Access Memory) has a read speed like that of SRAM, write speeds like that of DRAM, infinite endurance like that of SRAM and DRAM and low current consumption and voltage requirements. These are attractive features for a potential SRAM and possibly a DRAM replacement.

IBMIBM researchers have demonstrated MRAM devices with access times on the order of 2 ns, somewhat better than even the most advanced DRAMs built on much newer processes (according to the Wikipedia article on MRAM). Compared to Flash Memory, MRAM is faster on reading and writing, can operate on lower voltage levels and has infinite endurance vs. the finite endurance of flash memory. These are attractive features, but flash memory is manufactured in large volumes, making the price of flash memory chips much lower than MRAM chips.

MRAM is seen initially as a potential replacement for the more expensive SRAM since it has a read and write speed that approach SRAMs. MRAM is capable of much higher memory density than SRAM and it is non-volatile, unlike SRAM. Thus in volume the cost of MRAM can be lower for a given capacity. A system designer might use MRAM for a much larger but somewhat slower non-volatile cache memory.

If MRAM can become competitive to SRAM and the production volume increases it is possible that MRAM could also make some penetration into the DRAM market. MRAM is one candidate for in-development non-volatile memory computer architectures. NV memory and computer architectures and software built around the use of NVM could have a dramatic impact on end user experiences by providing state preservation of the machine even after the power is turned off.

The table compares MRAM memory with Flash Memory DRAM and SRAM. The table shows that MRAM may be able to provide the required data rates and act as a persistent memory replacement for DRAM and possibly SRAM. In particular MRAM is starting to show up as a cache memory in some applications.

SRAM

DRAM

Flash Memory

MRAM

Read Speed

Fast

Medium

Medium

Fast

Write Speed

Fast

Medium

Slow

Medium

Volatile

Yes

Yes

No

No

Endurance

Infinite

Infinite

Limited

Infinite

Low Voltage

Yes

Limited

Limited

Yes

Power Consumption

High

High

Low

Low

Everspin announced that its ST-MRAM has been incorporated as cache memory in a Buffalo Memory SS6 SATA III SSD. The Everspin announcement says the “… cache improves tolerance for sudden power loss and reduces power consumption. SATA III runs up to 6.0 Gigabits per second, twice the rate of SATA II, which improves quality of service in high data rate applications.”

The only MRAM company currently shipping product is EverSpin. In August 2013 EverSpin announced that it had shipped a total of 10 M MRAM chips (up from 4 M at the end of 2011). EverSpin’s largest chip capacity is 64 Mbits compared to DRAM chips in the multiple Gbit size. This is reflection of the much larger feature sizes currently used in MRAM production. Besides EverSpin, other companies designing MRAM products include Aeroflex (licensing Everspin MRAM technology), Avalanche Technology and Crocus. The latter two companies are independent start-ups focusing on making MRAMs. Grandis, another MRAM start-up, was acquired by Samsung in 2011.

MRAM has been scaled up and achieved some niche market applications by EverSpin. However reaching beyond the current niche markets requires ramping production further and to date nobody has stepped up to fund the sort of investment required for mass production of another solid-state storage technology. While there are some tools that can be used for DRAM, SRAM and MRAM, the magnetic technology in MRAM requires significantly different equipment.

MRAM is a promising solid-state storage technology but it has been difficult to ramp beyond current limited niche markets. Perhaps cache memory is the “Killer App” for MRAM and can create a justification to build up manufacturing capacity for MRAMs that will be required to lower overall production costs and to create a virtuous cycle of ever-lower costs and ever-higher demand. Memories may be sometimes forgotten, but non-volatile memories, such as MRAM may be here to stay.

Post Your Comment

Post Your Reply

Forbes writers have the ability to call out member comments they find particularly interesting. Called-out comments are highlighted across the Forbes network. You'll be notified if your comment is called out.